Beyonce has cancelled a date on her Mrs Carter world tour amid persistent rumours she is pregnant with her second child.

The singer blamed the cancellation on 'dehydration and exhaustion' and said her doctor had advised her to rest.

She was scheduled to perform in Belgium at the Sportpaleis in Antwerp on Tuesday night but the concert will now be rescheduled.

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Pregnant? Beyonce has now cancelled a gig on her Mrs Carter tour blaming exhaustion, adding to the reports she is pregnant after been seen sporting an uncharacteristically rounded stomach

Wednesday's concert is also in doubt. In an email to The Associated Press, the singer's publicist
said Beyonce 'is awaiting word from her doctors before making a
decision' about whether she can perform.

The cancellation comes amid reports the 31-year-old is expecting her second child with husband Jay Z.

The New York Post newspaper claims 'multiple sources' told them Beyonce is pregnant following her attendance at the star-studded Met Ball last week, where the star's rumoured pregnancy was the talk of the night.

Baby number two? Beyoncé's Met Gala look was reportedly designed to conceal her growing tummy

The pop superstar is said
to have 'carefully' hidden her baby bump in a high-waisted Givenchy
gown, but multiple photos have since surfaced of Beyonce sporting a
growing stomach on her 65-date Mrs Carter Show world tour, which
touched down in Dublin, Ireland, on Sunday.

Pictures of her on stage in London appear to show an uncharacteristically rounded tummy.

The Grown Woman singer welcomed her first child, daughter Blue Ivy
Carter, into the world in January 2012.

Ubiquitous: The star is everywhere at the moment, while touring the world with her Mrs Carter, her H&M ads have been springing up across the world

Beyoncé and Jay-Z - real name
Shawn Carter - remained tight-lipped about her first pregnancy until
sensationally announcing it live at the MTV Video Music Awards in August
2011.

Beyoncé
recently admitted she would love to give her 18-month-old daughter a
sibling, because she enjoyed such a close relationship with her younger
sister Solange Knowles, 26, when they were growing up.

She said: 'I would like more children. I think my daughter needs some company. I definitely love being a big sister.'

Who runs the world? The star, unfazed by criticism, is on the European leg of the tour before moving on to North America

When pressed on when she may have another child, she added: 'At some point, when it's supposed to happen.'

However a source tells People magazine the baby may not be on the way just yet: 'Beyonce and Jay are planning for another baby after her tour is over and things calm down just a bit.'

In other family matters, Beyoncé's father Matthew Knowles has reportedly been landed with an approximately $1.2 million tax bill.

TMZ say the IRS claim he still owes taxes from 2010-2011, the years in which Matthew was still managing his daughter as well as his own record label.

The government has allegedly filed a large lien against Knowles, claiming he needs to pay $485,575.95 from 2010 and $728,004.89 from 2011, which comes to a total of $1,213,580.84.

Baby daddy: Jay-Z and Beyoncé welcomed their daughter into the world in January 2012